A381859 - cp's OEIS frontend

A381859 a(n) is the number of permutations that avoid 312 and 4321 and whose square avoids 321.

n	a(n)
0	1
1	1
2	2
3	5
4	11
5	23
6	50
7	109
8	236
9	511
10	1108
11	2402
12	5206
13	11284
14	24459
15	53016
16	114914
17	249081
18	539894
19	1170243
20	2536551
21	5498082
22	11917326
23	25831309
24	55990457
25	121361689
26	263056605
27	570186341
28	1235903062
29	2678872272
30	5806569196
31	12585984849
32	27280655629

[1, 1, 2, 5, 11, 23, 50, 109, 236, 511, 1108, 2402, 5206, 11284, 24459, 53016, 114914, 249081, 539894, 1170243, 2536551, 5498082, 11917326, 25831309, 55990457, 121361689, 263056605, 570186341, 1235903062, 2678872272, 5806569196, 12585984849, 27280655629]

cp's OEIS Frontend

A381859 a(n) is the number of permutations that avoid 312 and 4321 and whose square avoids 321.

Table of values

List of values